The invention relates generally to a device and system for making electrical connection to an electrolyte, and especially to such device and system in which electrical connection is provided to an electrolyte contained within a length of tubing extending into a human body, as is the case in a catheter electrode, for example.
There are a variety of applications in which it is desired to provide an electrical connection to an electrolyte within a catheter inserted into the human body, and it is with respect to such applications that the present invention will be described in detail.
A specific use of such an arrangement is in right atrial electrocardiography (RAECG). In this technique a catheter containing an electrolyte in the form of an ionic salt is inserted into the right atrium of a human heart to serve as a right atrial electrode. That is, the electrically-conductive electrolyte serves as a long electrode extending from the atrium to a portion of the catheter external to the body where an electrical connection is made to the electrolyte to derive the desired measurements with respect to electrical activity within the atrium. Such RAECG is a known technique for facilitating central venous catheter placement, for more accurately diagnosing atrial dysrhythmias, and for recognizing posterior myocardial ischemia/infarction.
In order to make the necessary electrical connection to the electrolyte at a point external to the body, it has previously been the custom to employ an all-metal stopcock in line between the catheter tubing and the source of the electrolyte; a sterilized alligator clip was secured to the all-metal stopcock, and a conductive lead attached to the alligator clip constituted the ECG lead by which the electrical variations to be studied were carried from the alligator clip to the ECG monitor.
A similar arrangement has been used in connection with the administration of regional block anesthetic in liquid form, where the liquid anesthetic, such as lidicane, is electrically conductive and is delivered from a syringe through a catheter-over-needle device to the site of the nerve to be anesthetized. By applying a low voltage to the electrolyte, the nerve is caused to twitch when the needle has been inserted to the desired point where the liquid anesthetic reaches the nerve site, the nerve twitch providing an indication to the anesthetist that he has reached the desired site. For this purpose also it is known to use an all-metal stopcock as the electrode to which the external voltage is applied.
Such an all-metal stopcock and alligator clip arrangement is relatively expensive, as a result of which it cannot economically be discarded after use and hence must be resterilized on each occasion of its reuse; also, since its exterior is of metal it is exposed to anomalous environmental electrical currents due to chance grounding or leakage currents, which may interfere with the desired ECG display and possibly do injury to the patient.
Accordingly, it is an object of the invention to provide a new and useful device and system for providing electrical connection to an electrolyte.
Another object is to provide such device and system which is especially adapted for making electrical connection to an electrolyte used as a liquid electrode extending through a catheter into the human body.
A further object is to provide such device and system which is very inexpensive to make and hence can economically be discarded after each use, thus avoiding the need for sterilization upon each reuse.
It is also an object to provide such apparatus in which the electrical connection is completely insulated from the environment during use.
A still further object is to provide such a device which is quick and easy to insert into the electrolyte system.